1. Field of the Invention:
The present invention relates to an electrical device control system for controlling a plurality of electrical devices with a time division multiple signal system.
2. Description of the Prior Art:
Heretofore, in the case of controlling a plurality of electrical loads with corresponding control switches, the electrical loads have been connected with the switches according to control considerations. FIG. 1 shows one simplified embodiment of the conventional system. In FIG. 1, the reference numeral 1 designates a power source; 2, 3, 4 designate control switches; 5, 6, 7 designate the electrical loads being controlled; 8a, 8b, 9a, 9b, 9c, 9d designate the respective electrical wirings connecting the power source 1 with the control switches 2, 3, 4 and the electrical loads 5, 6, 7 depending upon the control considerations.
The embodiment of FIG. 1 can be utilized for various sequence control devices; electrical systems of cars; call-indicating devices in a factory, valve controls of a tanker ship, etc. However, even in the simple case of FIG. 1, 6 wires have been required for the electrical wirings. In this case, the return lines from the electrical loads 5, 6, 7 to the power source 1 are to ground. If the return lines are separately formed, an additional three wires are required. As it is clear from this discussion, when the number of the electrical loads or the control switches is increased, the electrical wiring for the connections becomes complicated with the result that erroneous wirings and faults are increased. Moreover, both fault detection and maintenance have become difficult. If the control switches are changed, the connections of the electrical wirings must also be changed. If many control switches are used, the necessary rewiring is often difficult to accomplish. Moreover, when the control switches are separated from the electrical loads by a long distance, the length of the electrical wires causes additional problems.